A telecommunications system usually comprises a communications network and a plurality of telecommunications nodes which communicate through said network, wherein each node is arranged to perform one or a set of specialized functions so as to serve telecommunication services to the users of said system. A telecommunications node is a functional entity that, depending on construction details, can be implemented within a single physical machine, or can be distributed across various physical machines, each implementing a part of the total functionality required and/or standardized for said node.
While the number of nodes in a telecommunications system has traditionally depended on factors such as: the total number of users the system is intended to serve, or the geographical distance of the user terminals of these users; the different kind of nodes within a concrete telecommunications system are more dependent on its specific characteristics.
For example, legacy telecommunications systems, such as Public Switched Telephone Network PSTN systems, were essentially comprised of routing nodes, arranged to handle (routing, processing, etc) signaling messages originating or terminating in user terminals.
As opposed to legacy telecommunications systems, which assumed a given user to be permanently associated to a fixed point of attachment for his user terminal, some modern telecommunications systems provide dynamic registration capabilities. These telecommunications systems allow a user to register and deregister his presence in the system from a user terminal which, in most of the cases, does not need to attach to the system from the same access point. This is commonly accomplished by sending, respectively, registration and deregistration messages from the user terminal to the telecommunications system, which updates the registration information of the user accordingly. The registration information usually comprises the registration status of the user (e.g. if registered or unregistered) and information usable to find the routing node assigned to handle signaling to/from the terminal of said user.
Examples of modern telecommunications systems as referred above are: Global System for Mobile Communications GSM, also known as 2nd Generation 2G mobile systems; Universal Mobile Telecommunications System UMTS, also known as 3rd Generation 3G mobile systems; and systems based on modern multimedia communications protocols, such as H.323 based systems (e.g. as defined in ITU-T H.323; July 2003) or Session Initiation Protocol SIP based systems (e.g. as defined in IETF RFC3261; June 2002). An example of the latest is the so called IP Multimedia Subsystem IMS (e.g. as defined in 3GPP TS 23.228 V7.3.0; March 2006).
The need of providing a dynamic registration capability for users has driven a trend for devising modern telecommunications systems comprising, not only routing nodes, but location registration nodes arranged to handle registration information of the users. For example, in 2G mobile systems Mobile Switching Centers MSC or Serving GPRS Support Nodes SGSN are routing nodes, and Home Location Registers HLRs are location registration nodes. In IMS systems, the so called Call Session Control Function CSCF nodes perform as routing nodes while the Home Subscriber Servers HSS perform as location registration nodes. In short, registration and deregistration messages from a user terminal are received in a routing node, which notifies the registration event (e.g.: initial registration, re-registration, deregistration) to a location registration node. The location registration node then updates the registration information concerning to the user of the terminal accordingly.
Additionally, the need of providing new kind of telecommunications services beyond the traditional user-to-user communications, or in addition to them, has caused also the appearance of new kind of nodes (generally known as “application servers” AS) specialized in providing the final service to the user, or to mediate in said provision. Examples of these kinds of nodes are Presence Servers or Network based Watcher Application Server (e.g. as described in: 3GPP TS 23.141 V7.1.0; December 2005, or 24.141 V7.1.0; March 2006), SIP Application Servers (e.g. as defined in the aforementioned 3GPP TS 23.228) or Push-to-talk PoC server (e.g. as described in 3GPP TR 23.979 V6.2.0; June 2005).
In addition to some already standardized services cited above as examples, a plurality of new services can also be envisaged, which can be provided from, or through, a telecommunications system (e.g.: an information service based on user location, such as local weather or local taxi information; mediation for electronic commerce; etc). However, as in the example cases cited earlier, the implementation of these new services will, in most of the cases, also require specialized application servers, and the cooperation of other nodes in the telecommunications system with these application servers; for example, for routing the signaling and/or media related to the services, or for obtaining additional information (e.g. current location, authentication assertions, user information such as preferred language, etc).
In summary, modern telecommunications systems have become more complex, as they tend comprise a plurality of different kind of nodes and tend to offer more and more services. However, as opposed to legacy telecommunications systems offering essentially basic voice communication services, the traffic load in some nodes of some modern systems is not so directly related to the total number of users who are subscribed to it, since some services are only provided upon user request and, for example, a given user can make a frequent use of some service(s) and a very scarce, or even null, use of some other service(s). In this situation, is then conceivable that the operator of a telecommunications system can be interested in obtaining information about the usage rate of some of the resources of the system for several reasons.
A first reason is, for example, to better dimensioning some system resources, such as the number of nodes of a given type and/or the capacity of said nodes. For example, in case an operator desires to offer a new kind of service, a deployment strategy can be to first make the service available to a set of selected users. Then, according to the usage rate during a given period, the operator can estimate what could be the total rate usage in case the service is made available to all its subscribed users, and thus, for example, the number of application servers needed to provide the service and their required capacity. Accordingly, the obtainment of user activity information in a simple way, minimizing the impact in the signaling and in the nodes of the telecommunications system, is highly desirable.
A second reason relates to pricing criteria when acquiring telecommunications equipments from technology providers. A typical pricing parameter for some telecommunications nodes uses to be related to the rate of usage of the node; for example, related to the maximum number of users that can be configured to be served in said node. As those skilled know, in computer-based telecommunications nodes this can be accomplished by a specific software which controls that the rate usage does not exceed the acquired “usage licenses”.
Thus, when acquiring, for example, a HLR or a HSS, the price agreement between the operator and the provider of the node can be established depending on the number of users whose subscriber data can be configured in said node and who shall be served for registration information from it. Similarly, when acquiring an application server, the price agreed with the provider can, for example, depend on the number of users who can subscribe to the service provided from that node and/or, depending on the nature of the service, depending on the number of users whose relevant data can be configured therein so as to receive the service.
However, what commonly provides a benefit for the operator of a telecommunications system is not the number of users the system can attend for any of the services it can provide, but the usage of these services. Thus, it is understandable that some operators may desire to agree with the technology providers the price of some nodes, not merely based on their capacity (e.g.: based on the number of users that can be configured and/or served by the node), but according to the usage rate of the services provided from said node, or through its intervention. This can require the agreement of the final price to be fixed after some time in operation of the node(s) in question, and, for this purpose, the collection of user activity information in a simple way, minimizing the impact in the signaling and in the nodes of the telecommunications system, is also desirable.